We found this circuit in a magazine 73 from the 90's. It is a circuit indicated for radio-amateur transmitters with the frequencies determined by the sets of coils.
The integrated circuit used in this 2002 project is not very common. It is powered directly by the...
We found this circuit in a 1972 RCA technical documentation. The comparator can be any type and C1...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...